Coated structural units having improved physical properties

ABSTRACT

The disclosure of this application is directed to structural units, as for example, structural units of concrete, wood, paper, bradish cloth and the like to be used in the construction, building and other like industries, which are coated with a composition based on an alkali metal silicate, a sodium tripolyphosphite wetting agent and a filler to provide structural units having improved &#39;&#39;&#39;&#39;sealant&#39;&#39;&#39;&#39; and fire-resistant characteristics.

AU lib X5 1 398549937 Michael, deceased United States Patent [191 Dec.17, 1974 COATED STRUCTURAL UNITS HAVING IMPROVED PHYSICAL PROPERTIESDavid H. Michael, deceased, late of 3210 Five Oaks Place, Louisville,

Ky. 40207 by Margaret C. Michael, legal representative Filed: Jan. 2,1973 Appl. No.: 320,189

Inventor:

US. Cl. 117/123 A, 52/515, 106/74, 106/84,117/123 B, 117/123 C, 117/147,117/152, 117/169 A Int. Cl C09d l/02, B32b 13/04 Field of Search 117/123A, 123 B, 123 C, 117/169 A; 106/74, 84; 52/515 References Cited UNITEDSTATES PATENTS 7/1889 Catlin 106/84 1,942,299 1/1934 Lemmerman et a1106/74 1,989,833 2/1935 Ware 106/84 2,449,346 9/1948 Vannoy 106/842,756,159 7/1956 Kendall 106/84 3,180,746 4/1965 Patton et a1. 106/843,511,692 5/1970 Pratt 117/123 A Primary ExaminerWilliam D. MartinAssistant Examiner-William H. Schmidt [57] ABSTRACT "ing improvedsealant and fire-resistant characteristics.

3 Claims, N0 Drawings COATED STRUCTURAL UNITS HAVING IMPROVED PHYSICALPROPERTIES This invention relates to coated structural units which arecharacterized by improved properties. More particularly, this inventionrelates to structural units having wide utility in the construction,building and other like industries, as for example, structural units ofconcrete, wood, paper, bradish cloth and the like which are coated witha composition based on an alkali metal silicate, a wetting agent and afiller to provide coated structural units having improved sealantcharacteristics, i.e., structural units which are air-tight and havingimproved fire-resistant properties.

In current day mining operations, for instance, coal mining operations,good ventilation for the miners is essential to the safe and efficientoperation of the mine. In order to provide the necessary ventilation,air is forced through the mine and directed to the desired areas bymeans of so-called stoppings. Stoppings are structural walls usuallymade of concrete which are used to block passages of the mine and todivert the air being forced through the mine to the working and otherdesired areas. As a rule, the stoppings are temporary walls and movedfrom location to location, as the need arises. Also, these stoppings aremade air tight usually using cement and plaster, in order that theyprovide efficient blocking" action with respect to the air being forcedthrough the mine.

it has been found, however, that plastering of the stoppings is a timeconsuming and expensive operation. Furthermore. the resultant plasteredsurface is usually brittle and is easily damaged. Consequently. thestoppings require constant repair in order to maintain airtight"characteristics.

The present invention provides coated structural units having excellentsealant characteristics, are resistant to surface damage and in additionare characterized by improved fire resistant properties.

The structural units of this invention, as stated, are coated with acomposition based on an alkali metal silicate, a wetting agent and afiller.

Examples of suitable fillers for purposes of this invention arefilamentous material such as inorganic fibers exemplified by asbestosfibers, steel wool fibers, bronze fibers, glass fibers and the like;organic fibers, such as cellulosic fibers, polyacrylonitrile fibers andthe like rendered infusible by heat-treatment, polyethylene,polystyrene, polyurethane and the like. Particularly desirablefilamentous materials are the asbestos fibers. Other suitable fillersare granular materials such as barium sulfate. cork dust, silica, mica,metal particles, clay, litharge, calcium oxide, zinc oxide, zinc dust,graphite. molybdenum disulfide, iron oxide, Cardolite resins which arereaction products of an aldehyde and cashew nut shell oil described indetail in U.S. Pat. No. 2.317.587. and the like.

Illustrative of alkali metal silicates are the sodium and potassiumsilicates as well as the commercially available. silicates which aresold by Philadelphia Quartz Co. as sodium silicate solution K and byDiamond Alkali as sodium silicate solution 47. Generally, these aqueouscommercial solutions contain at least about l.5 moles Si per mole Na- O.preferably about [.5 to about 3.75 moles SiO- per mole of M1 0 and evenmore preferably about 2 to about 3 moles of SiO; per mole of Na O.

The wetting agents are well-known materials and are exemplified by thepolyphosphites, silicones, ethoxylated alcohols, organo polysiloxanes,silicones and the like. Commercially these wetting agents are sold underthe trade name of Tergitol, MinFoam, lX, NPX, 12-M- 10, Tween 20,Dow-Corning 199.

Formulation of the coating composition can be effected by simplyadmixing the components thereof in a Hobart mixer or a dough mixer. Thealkali metal silicate, usually as an aqueous solution is charged intothe mixer and the wetting agent and filler added thereto with agitation.Sufficient water is added and mixing is continued until a smooth coatingsolution or composition is obtained.

The resultant composition can then be applied by any conventionalcoating techniques, spraying, brushing, troweling and the like.

The thickness to which the coating is applied is not critical. Coatingsless than about 5 mils effect air-tight surfaces.

The amount of filler and wetting agent relative to the amount of alkalimetal silicate on a solids basis is, with respect to the filler aboutone percent by weight to about percent by weight, based on the weight ofthe silicate and with respect to the wetting agent, about 0.5 to about10 percent by weight, based on the weight of the silicate.

The following examples further illustrate the present invention.

EXAMPLE 1 A composition, the formulation of which is noted below, wasprepared in a Hobart mixer to a coating composion of a smooth, uniformconsistency.

PARTS BY WElGHT Sodium Silicate (Aqueous solution containing 40 percentsodium silicate on a solids basis) 25 Asbestos 5 Sodium Tripolyphosphite(Calgon) 0.2

This coating composition was used to coat the following masonrystructural units:

1. cinder blocks 2. cement blocks The structural units were air-tightand fire-resistant.

EXAMPLE 2 A composition. the formulation of which is noted below, wasprepared in a Hobart mixer to a coating composition of a smooth, uniformconsistency.

PARTS BY WEIGHT Sodium Silicate (described in Example I 46 Asbestos 4.5

-Continued PARTS BY WEIGHT Sodium Tripolyphosphite (Calgon) 0.4

Structural units of wood, paper and bradish cloth were also coated withcompositions of Example I and 2 with equally good results.

What is claimed is:

l. A structural unit of concrete or cinder block coated with acomposition consisting essentially of an aqueous solution of an alkalimetal silicate containing at least about 1.5 moles SiO per mole Na O, afiller and a sodium tripolyphosphite wetting agent, wherein said filleris present in an amounm to about percent by weight, based on the weightof said silicate and said wetting agent is present in an amount of about0.5 to about 10 percent by weight, based on the weight of said silicate.

2. A structural unit as defined in claim 1 wherein the said silicatecontains about 1.5 to about 3.75 moles SiO per mole N320.

3. A structural unit as defined in claim 1 wherein the filler of thecomposition is asbestos.

1. A STRUCTURAL UNIT OF CONCRETE OR CINDER BLOCK COATED WITH ACOMPOSITON CONSISTING ESSENTIALLY OF AN AQUEOUS SOLUTION OF AN ALKALIMETAL SILICATE CONTAINING AT LEAST ABOUT 0.5 MOLES OF S PER MOLE NA2O, AFILLER AND A SODIUM TRIPOLYSPHOSPHITE WETTING AGENT WHEREIN SAID FILLERIS PRESENT IN AN AMOUNT OF ABOUT ONE TO ABOUT 100 PERCENT BY WEIGHT,BASED ON THE WEIGHT OF SAID SILICATE AND SAID WETTING AGENT IS PRESENTIN AN AMOUNT OF ABOUT 0.5 TO ABOUT 10 PERCENT BY WEIGHT, BASED ON THEWEIGHT OF SAID SILICATE.
 2. A structural unit as defined in claim 1wherein the said silicate contains about 1.5 to about 3.75 moles SiO2per mole Na2O.
 3. A structural unit as defined in claim 1 wherein thefiller of the composition is asbestos.